Antioxidants for mineral oil lubricants and compositions containing the same



Patented July 25, 1950 UNITED [STATES M'PATEN/T' I iANTIOXIDANTS FORCANTS AND'COMPO THE SAME 2,516,654 OFFlCE MINERAL OIL LUBRI- SITION SCONTAIN Herschel G'..Smith, Wallingford, and Troy L. cantroll,Lansdowne, Pa., andJohn G. Peters; Audubon, N. .L, assignors to Gulf OilCorporation,

Pittsburgh. Pa.,

a corporation of Pennsylvania 7 No Drawing.- Application January 6,1949,

Serial No. 69,614 g is Claims. (Cl. 252-415 .This invention relates toantioxidants for mineral oil 'lubricants and compositions containing thesame, and more particularly, it relates to addition agents for mineraloil lubricants which surfaces of varnish, gum or sludge. I Furthermore,

many'lubricating oil compositions which may be highly satisfactory forthe lubrication of other mechanisms have been found wholly unsuitablefor use as turbine oils.

The formation of varnishes, gums and sludges on engine surfaces is dueat least in part to oxidation effects on mineral lubricating oils. Inturbine oils the problem of oxidation is further aggravated, because innormal use turbine oils rapidly become contaminated with water.

It is an object of this invention, therefore, to provide an additionagent for mineral oil lubricants which will'inhibit the oxidativedeterioration of such lubricants;

It-is further an object of this invention to provide mineral oillubricant compositions which are remarkably stable against oxidationunder service conditions.

These and other objects are accomplished by the present inventionwherein an addition agent for mineral oil lubricants is prepared bycon-- densing phenyl morpholine, N-dimethylaniline and formaldehyde inthe presence of an activated clay as a catalyst, and recovering thecondensation product. The condensation product so obtained isalight-colored product which, when added to mineral oil lubricants,confers a remarkable stability against deterioration by oxidation. Suchcondensation products and mineral oil lubricant compositions containingthem are believed to be novel and are considered parts of our.invention. Contrary to what may be expected from the-nature of thereactants, we do not obtain highly-condensed, insoluble resinousproducts. When the above reactants are condensed in accordance with ourinvention, there are obtained light colored condensation products whichare non-resinous and which are readily soluble in mineral oils.

In performing the condensation the reactants are mixed and heated to amaximum tempera-- ture of 350 F. We have found that if the temperatureof 350 F. is exceeded to any substantial extent, the condensationproduct formed tends to be resinous and insoluble. In general,

-'the preferred temperature for the condensation ranges from 160 to 220F.

The proportions of the reactants vary as follows: For eachmol of phenylmorpholine, N-dimethylaniline is employed in an amount of from 2 to 6mols, and the formaldehydeis employed in an amount from 2 to 6 mols.Ordinarily, it is preferred to use from 5 to 10 per cent by weight ofthe activated clay catalyst, based on the total weight of the reactants.However, smaller amounts, as low as 1 per cent by weight, and largeramounts, as high as 20 per cent by weight, may also be employed; butlarger amounts than about 10 per cent byjweight are ordinarily notnecessary.

The phenyl morpholine referredto herein has the formula:

CHr-CH:

In lieu of formaldehyde any formaldehydemorillonite, fullers earth,floridin and smectite,

which has been acid treated in order to activate the clay. Thesematerials are described in U. S. Patent 1,898,165, for example.

In preparing our new addition agents, the reactants and catalysts areplaced into a reaction vessel which is then closed and the mixtureheated with agitation under reflux until all of the formaldehyde orformaldehyde-yielding compound has been consumed. At this time the waterwhich is formed as a result of the condensation is removed, preferablyunder vacuum, and the dehydrated condensation product is then filteredto remove the activated clay catalyst. In some instances, it isdesirable to prepare our new addition agent in a concentrate in amineral lubricating oil which may then be diluted down with additionaloil to the concentration desired in the final lubricating composition.In such instances, the mineral lubricating oil may be added in asuitable amount, say in a weight equal to the weight of reactants, tothe reaction mixture in the reacance with the above disclosure tionvessel. and the condensation product obtained will then be aconcentrated solution of the addition agent in the mineral lubricatingoil.

The condensation products obtained in accordance with our invention areliquids or crystalline solids. While the exact nature of the chemicalcomposition of the condensation products is unknown, all of the threereactants enter into a final unitary product. The exact nature of themanner in which the catalyst influences the reaction is unknown.However. regardless of any theory involved, the use of an activated claycatalyst is an essential feature of our invention, since if the catalystis omitted, black, insoluble, resinous condensation products areobtained.

The following examples illustrate the preparation of our new additionagent.

Example I.Into an enamel-lined reaction vessel were charged 163 poundsof phenyl morpholine (1 pound moi), 363 pounds of N-dimethylaniline (3pound mols), and 243 pounds of a 37 per cent by weight aqueousformaldehyde solution (3 pound. mols of anhydrous formaldehyde) alongwith 62 pounds of an activated clay (Filtrol) as a. catalyst. Themixture was refluxed and agitated at 280 F. for a period of 5 hours, andthen all water, both that added with the formaldehyde and formed in thereaction, was distilled oil. The product was then filtered and had thefollowing properties:

Gravity, API 3.5 Color, NPA 4.75 Neutralization No 1.00

Gravity, API 4.1 Color, NPA 3.5 Neutralization No 0.7

Example III.--Another reaction product was prepared by reacting 1 mol ofphenyl morpholine, 3 mols of N-dimethylanilineand 6 mols of formaldehydein the presence of 5 per cent by weight of the total reactants of anactivated clay catalyst under the conditions set forth in Example I. Theproduct had the following properties:

Gravity, API 3.7 Color, NPA 11.0, Neutralization No 0,6

The condensation products obtained in accordfrom phenyl morpholine,N-dimethylaniline and formaldehyde in the presence of an activated claycatalyst are excellent addition agents for mineral oil lubricants. Theyare readily soluble in all types of mineral oils, that is, parafllnic,naphthenic or mixed base mineral oils in high proportions to formconcentrated solutions thereof, which may then be diluted down to theproportions desired in the final mineral oil lubricant composition.

For this purpose small amounts of our new addition agents are generallysuflicient For example, our addition agents may be added to minerallubricating oilsin minor amounts, say

from 0.001 to 1 per cent by weightof the mineral 4 oil, sunlcient toinhibit the oxidative deteriora The following examples illustrate theremark-' able antioxidant effects of our new addition agents. In thefollowing examples, the base oil and the same oil blended withour. newaddition agents aresubiected to a standard oxidation test which measuresthe stability of the oils to oxidation. The oxidation test referred tois a standard test designated ASTM D943-47T. Briefly, the test comprisessubjecting the oil sample to oxygen at a temperaturegof C. (203 F.) inthe presence of waterand an iron copper catalyst. and determining thetime required to--bulld up a neutralization number of 2. The flow ofoxygen ismaintained at 3 liters per hour.. dation of mineral oillubricant compositions containing our new addition agents is illustratedby the results shown in the following examples.

Example IV.To a steam a viscosity of 148 SUV at F. there was added 0.5per cent by weight of an addition agent prepared according to Example I.The base oil and the oil blended with the antioxidant were thensubjected to the above described standard oxidation test with thefollowing results:

hipiotgedmOil on n g 0.5% Antioxidant Gravity API 29.4 29.5 Oxidatio'nTest, ASTM D943-47T 203 F., 3 L Oxygen/Ha:

Time Oxidized, Hrs 180 2, Neutralization No..' g 2.0 2.0.

Example V.'To a motor oil which had been highly refined by aluminumchloride treatment there was added 0.5 per cent by weight of anantioxidant prepared according to Example I. A

The above examples show the remarkable oxidation stability imparted tomineral oil lubricant compositions by the use of our new additionagents. Mineral oil lubricant compositions containing our new additionagent are therefore eminently suited for use where the operatingconditions are extremely severe, as in Diesel, tank and truck engines,and in the lubrication of steamturbines.

The remarkable effects of our new addition agents cannot be readilyaccounted for and cannot be predicted from the nature of the reactants.Thus, condensation products prepared from other functionally similarcompounds have been found to be either prooxidant or to show noantioxidant effects whatsoever. For example, we have prepared acondensation product similar to our new addition agent by substitutingxylidine for the N- dimethylaniline. The resulting condensation productwas'found to be entirely unsuitable for The remarkably effectivestability to oxiturbine oil having 1 our invention is not limitedthereto but comprises all mineral oil lubricant compositions containingour new addition agents, such as greases and the like.

Resort may be had to such modifications and variations as fall-withinthe spirit of the invention and the scope of the appended claims.

We claim.

1. The process of preparing an addition agent for mineral oil lubricantswhich comprises heating phenyl morpholine with from 2 to 6 mols ofN-dimethylaniline and 2 to 6 mols of formalde hyde per mol of phenylmorpholine in the presence of an activated clay catalyst at atemperature not in excess of 350 F. to condense together the threereactants, and recovering the condensation product.

2. The process of preparing an addition agent for mineral oil lubricantswhich comprises heating phenyl morpholine with from 2 to 6 mols ofN-dimethylaniline and, 2 to 6 mols of formaldehyde per mol of phenylmorpholine inthe presence oi 5,to 10 percent by weight of the totalreactants of an activated clay catalyst at a temperature of from 160 to220 F. to condense together the three reactants, and recovering thecondensation product.

3. The process of preparing an addition agent mmineral oil lubricantswhich comprises adding an activated clay catalyst, phenyl morpholinewith from 2 to 6 mols of N-dimethylaniline and 2 to 6 molsof'formaldehyde per mol of phenyl morphoiine to a mineral lubricatingoil, heating the mixture to a temperature not in excess of- 350 F. toform a condensation product. and recovering a solution of thecondensation product in the mineral lubricating oil.

' 4. The processoi preparing an addition agent for mineral oillubricants which comprises heatin: 1 mol of phenyl morpholine, 3 mols ofN-dimethylaniline, and 3 mols of formaldehyde in the presence of anactivated clay catalyst at a temperature of from 160to 220 F. tocondense togather the three reactants, and recovering the condensationproduct.

5. The process of preparing an addition agen for mineral oil lubricantswhich comprises heating 1 mol of phenyl morphcline, 6 mols of'N-dimethylaniline and 6 mols of formaldehyde in the presence of anactivated clay catalyst at a temperature of from 160 to 220 F.'tocondense together the three reactants, and recovering the condensationproduct.

6. The process of preparing an addition agent for mineral oil-lubricantswhich comprises heating 1 mol of phenyl morphcline, 3 mols ofN-dimethylaniline and 6 mols of formaldehyde in the presence of anactivated clay catalyst at a tem perature of from 160 to 220 F. tocondense together the three reactants, and recovering the condensationproduct.

7. A non-resinous condensation product of phenyl morpholine with from 2to 6 mols of N- dImethylaniIine and 2 to 6 mols of formaldehyde per molof phenyl morphcline, said product bein: obtained by the process orclaim 2.

8, Anon-resinous condensation product of 1 'mol of phenyl morphcline, 3mols of N-dimethylaniline and 3 mols of formaldehyde, said product beingobtained by the process of claim 4.

9. A non-resinous condensation product of 1 mol of phenyl morpholinewith 6 mols of N-dimethylaniline and 6 mols of formaldehyde, saiddeterioration of said 011 of a non-resinous condensation product ofphenyl morpholine with from 2to 6 mols of N-dimethylaniline and 2 to 6mols of formaldehyde per mol of phenyl morpholine, said product beingobtained by the process of claim 1.

12. A lubricant composition comprising a major amount of a minerallubricating oil, and a minor amount, from 0.001 to 1 per cent by weightof said oil, of a non-resinous condensation product of phenyl morphoiinewith from 2 to 6 mols of N-dimethylaniline and 2 to 6 mols offormaldehyde per mol of phenyl morphcline, said product being obtainedby the process of claim 1.

13. A lubricant composition comprising a major amount of a minerallubricating oil, and a minor amount, suflicient to inhibit the oxidativedeterioration of said oil of a non-resinous condensation product of 1mol of phenyl morpholine, 3 mols of N-dimethylaniline and 3 mols offormaldehyde, said product being obtained by the process of claim 4.

14. A lubricant composition comprising a major amount of a minerallubricating oil, and a minor amount, suflicient to inhibit the oxidativedeterioration of said 011 of a non-resinous condensation product of 1mol of phenyl morpholinefG mols of N-dimethylaniline and 6 mole offormaldehyde, said product being obtained by the process ofclaim 5.

( 15. A lubricant composition comprising a major amount of a minerallubricating oil. and a minor amount, sufficient to inhibit theoxidativedeterioration of said oil of a non-resinous condensation product of 1mol of phenyl morphcline, 3 mols o1 N-dimethylaniline and 6 mols-offormaldehyde, said product being obtained by the process of claim 6.

HERSCHEL G. SMITH. TROY L. CANTRELL. JOHN G. PETERS.

REFERENCES CITED The following references are of record in the file 0!this patent:

"UNITED STATES PATENTS OTHER REFERENCES Tseou et 9.1., ChemicalAbstracts, vol. 31 (1937). pages 1811 and 1812.

Certificate of Correction Patent No. 2,516,654 Jul 25, 1950 HERSCHEL G.SMITH ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 5, line 75, for the claim reference numeral 2 read 1 and that thesaid Letters Patent should be read as corrected above, so that the samemay conform to the record of the case in the Patent Ofiice.

Signed and sealed this 10th day of October, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,515,554 Jul 25, 1950 HERSOHEL G.SMITH ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 5, line 75, for the claim reference numeral 2 read 1 and that thesaid Letters Patent should be read as corrected above, so that the samemay conform to the record of the case in the Patent Oflice.

Signed and sealed this 10th day of October, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'ssioner of Patents.

1. THE PROCESS OF PREPARING AN ADDITION AGENT FOR MINERAL OIL LUBRICANTS WHICH COMPRISES HEATING PHENYL MORPHOLINE WITH FROM 2 TO 6 MOLS OF N-DIMETHYLANILINE AND 2 TO 6 MOLS OF FORMALDEHYDE PER MOL OF PHENYL MORPHOLINE IN THE PRESENCE OF AN ACTIVATED CLAY CATALYST AT A TEMPERATURE NOT IN EXCESS OF 350*F. TO CONDENSE TOGETHER THE THREE REACTANTS, AND RECOVERING THE CONDENSATION PRODUCT. 